Optimize document refresh;

Rather than redraw the whole screen on a document character change
we update the buffer and redraw only the document area.

Fixes #302.

lib/vedeu/editor/document.rb

@@ -173,7 +173,9 @@ def refresh
 
         Vedeu.trigger(:_clear_view_content_, name)
 
-        Vedeu.render_output(output)
+        Vedeu.buffer_update(output)
+
+        Vedeu.direct_write(output.map(&:to_s).join)
 
         self
       end

lib/vedeu/output/output.rb

@@ -9,6 +9,15 @@ module Output
     #
     class Output
 
+      # @param output [Array<Array<Vedeu::Views::Char>>|
+      #   NilClass|Vedeu::Models::Escape]
+      # @return [Array]
+      def self.buffer_update(output)
+        return nil if output.nil?
+
+        new(output).buffer_update
+      end
+
       # @param output [Array<Array<Vedeu::Views::Char>>|
       #   NilClass|Vedeu::Models::Escape]
       # @return [Array]
@@ -47,6 +56,11 @@ def initialize(output)
         @output = output
       end
 
+      # @return [Array]
+      def buffer_update
+        buffer_update!
+      end
+
       # @return [Array]
       def buffer_write
         buffer_write!
@@ -84,6 +98,11 @@ def render_output
 
       private
 
+      # @return [Array]
+      def buffer_update!
+        Vedeu::Terminal::Buffer.update(output)
+      end
+
       # @return [Array]
       def buffer_write!
         Vedeu::Terminal::Buffer.write(output)
@@ -106,13 +125,17 @@ def escape_sequence?
   # Write the given output to the configured or default renderers.
   #
   # @example
+  #   Vedeu.buffer_update(output)
+  #   Vedeu.buffer_write(output)
+  #   Vedeu.direct_write(output)
   #   Vedeu.render_output(output)
   #
   # @!method render_output
   # @return [Array|NilClass]
   def_delegators Vedeu::Output::Output,
-                 :render_output,
+                 :buffer_update,
                  :buffer_write,
-                 :direct_write
+                 :direct_write,
+                 :render_output
 
 end # Vedeu